This invention relates to a novel process and apparatus for producing a shark fin analog, i.e., a simulated food resembling a shark fin processed as a food.
Processed shark fins or ray fins have been cherished as an elegant food material for Chinese cuisine dishes such as soup. Particularly, with the recent trend in diet variety in foods, especially in elegant Chinese dishes, is widely sought after. Accordingly, the demand for shark fins is gradually increasing.
Shark fins practically utilized as the materials for soup or other dishes are processed products of muscle filaments existing between cartilage and skin of fins of shark or ray, having lengths, which may differ slightly depending on whether the product is a dried product or a frozen product, ranging on an average from about 50 to 100 mm. As to the thickness, the thickest portion is in the range from about 1.4 to 1.6 mm on an average. Shark fins generally have slender streamlined profiles in cross section, as shown in FIG. 3, with one end being thick and pointed at its tip, and other end extending slenderly as a tail. Of course, some fins are greater in size than those described above, and the fins with greater sizes are traded as higher class products. Further, shark fins have lustrous gold color or silver color and are highly valued as Kinshi (golden wings) or Ginshi (silver wings).
In ordinary cooking, Kinshi, etc. are produced from natural fins of shark or ray. A great number of process steps and much labor are required in production of these food products, such as repeated cycles of cooking under mild heating for a long time, removing bones and impurities, and immersing in water for several days. Also considerable experience and skill is necessary for successful cooking. Furthermore, depending on the conditions during production, only products of markedly inferior quality may sometimes be obtained. Thus, under the present circumstances, shark fins of high quality cannot be supplied in large amounts at low cost.
In view of the state of the art as described above, we have thought of producing a shark fin analog of high quality from gelatin. As is well known in the art, natural shark fins comprise primarily collagen, of which the amino acid composition is substantially equal to that of the collagen obtained from bones, skins or binding tissues of animals which are generally used as the starting materials for gelatin. On the other hand, the gelatin obtained from animal tissue collagen is today supplied and utilized widely as a product of stable quality at low cost in large amounts. Therefore, if the gelatin can be used as the starting material for production of a shark fin analog, it will become possible to supply food materials having flavor, nutritional values and other characteristics comparable to those of natural products at low cost.
In the prior art, it has been known to treat fibers of gelatin obtained by wet spinning of a neutral solution thereof with a hardening agent, followed by washing with water and drying, to produce an edible gelatin (Japanese Patent Publication No. 8615/1970). However, the edible gelatin prepared according to this method has proved to have a mouth-feel unlike that of shark fins and not satisfactory as compared with shark fins from natural resources. For example, it has low strength and cannot be formed to have a streamlined profile, and fabrication thereof into a shape similar to natural shark fins was impossible even when the gelatin concentration was decreased or increased. Besides, while sufficient resistance to hot water is necessary for use in a heated liquid such as soup, the edible gelatin obtained according to the prior art method becomes very soft when boiled in hot water, and even those subjected once to spinning fail to have a mouth-feel of shark fins. Further, because of the treatment with a hardening agent, the treated gelatin becomes hardened to exhibit a dry and crumbling feeling. There was also a drawback in the manufacturing steps including the drying step, in that a considerable amount of energy was consumed. Thus, the edible fibrous gelatin obtained according to the process of the prior art as described above has no satisfactory quality as an alternate for naturally produced shark fins and therefore could not be used satisfactorily as an elegant food material for Chinese dishes.